Container images

New containers are usually created from images. An image is a tar archive with configuration and the container filesystems, see the full specification.

When creating a new container, the user selects the image to be used. Images can be downloaded from remote repositories or files from the local filesystem can be used.

Images are described by several parameters:

vendor - the image provider, e.g. vpsadminos
variant - content description, e.g. minimal
arch - x86_64, x86 and so on
distribution - debian, ubuntu and so on
version - distribution version

To create a new container, osctld needs to know arch, distribution and version. vendor and variant are used just to describe the image, osctld is not using these parameters.

Using remote images

Command osctl ct new is used to create containers from images downloaded from remote repositories.

Available images

Images from remote repositories can be listed with osctl repo images ls:

[root@vpsadminos:~]# osctl repo images ls default
VENDOR       VARIANT   ARCH     DISTRIBUTION   VERSION               TAGS                                      CACHED
vpsadminos   minimal   x86_64   alpine         3.8                   -                                         -
vpsadminos   minimal   x86_64   alpine         3.9                   latest,stable                             -
vpsadminos   minimal   x86_64   arch           20190605              latest,stable                             -
vpsadminos   minimal   x86_64   centos         6                     -                                         -
vpsadminos   minimal   x86_64   centos         7                     latest,stable                             -
vpsadminos   minimal   x86_64   debian         8                     -                                         -
vpsadminos   minimal   x86_64   debian         9                     latest,stable                             -
vpsadminos   minimal   x86_64   devuan         2.0                   latest,stable                             -
vpsadminos   minimal   x86_64   fedora         29                    -                                         -
vpsadminos   minimal   x86_64   fedora         30                    latest,stable                             -
vpsadminos   minimal   x86_64   gentoo         20190605              latest,stable                             -
vpsadminos   minimal   x86_64   nixos          19.03                 latest,stable                             -
vpsadminos   minimal   x86_64   nixos          unstable-20190605     unstable                                  -
vpsadminos   minimal   x86_64   opensuse       leap-15.1             latest,stable                             -
vpsadminos   minimal   x86_64   opensuse       tumbleweed-20190605   -                                         -
vpsadminos   minimal   x86_64   slackware      14.2                  latest,stable                             -
vpsadminos   minimal   x86_64   ubuntu         16.04                 -                                         -
vpsadminos   minimal   x86_64   ubuntu         18.04                 latest,stable                             -
vpsadminos   minimal   x86_64   void           glibc-20190605        latest,latest-glibc,stable,stable-glibc   -
vpsadminos   minimal   x86_64   void           musl-20190605         latest-musl,stable-musl                   -

Examples

osctl ct new requires at least option --distribution, other parameters are optional. Unless --version is set, tag stable is used. --arch defaults to the host's architecture and the default vendor and variant as reported by the repository is used.

osctl ct new --distribution ubuntu myct01

With specific version:

osctl ct new --distribution debian --version 9 myct01

Using local images

To use images from local files, use command osctl ct import:

osctl ct import my-image.tar

If the image does not contain container ID, or if you wish to change it, use option --as-id:

osctl ct import --as-id myct01 my-image.tar

For more information, see container export/import and how to build images.